It is planned to carry out an extensive investigation of several areas of statistical methodology for the design and analysis of experimental studies, planned or observational, applicable to various areas of health research including cancer, toxicology, environmental health and epidemiology. The objective would be to provide more efficient statistical methods to achieve valid conclusions at less cost in terms of time and sample size. Among the problem areas to be considered are: (1) Statistical design and analysis of animal survival/sacrifice studies; (2) Design and analysis of animal cancer induction and treatment studies; (3) Sequential methods for clinical trials (including the topics of screening and early stopping); (4) General statistical problems related to the analysis of censored and incomplete response-time (e.g., survival) data.